Seat cushion

ABSTRACT

A seating cushion includes an upper layer that is secured to a lower layer. The upper layer includes a plurality of interconnected gel pockets and the lower layer includes a plurality of interconnected gas pockets. In one configuration, each layer is formed from two sheets of material that are joined together at a plurality of corners to form the pockets of the layer. The layers are secured together such that a pair of sheets are disposed in the middle portion of the cushion. The upper and lower layers may be joined to a resilient foam base.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Patent Application Ser. No. 60/576,230 filed Jun. 2, 2004, and U.S. Provisional Patent Application Ser. No. 60/576,715 filed Jun. 3, 2004; the disclosures of both are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. TECHNICAL FIELD

The present invention generally relates to seating cushions and, more particularly, to seating cushions designed for extended use situations such as office chairs, vehicle seats, and wheelchairs. Specifically, the present invention relates to the structure of a seating cushion that includes both gel and air layers. The invention also relates to the method of manufacturing the cushion.

2. BACKGROUND INFORMATION

Those who sit for extended period of time at office chairs or as drivers desire comfortable seat cushions that minimize pressure points. Those who are forced to use wheel chairs for long periods of time desire seat cushions that minimize the risk of sores caused by pressure points. All seat cushion users desire comfortable seat cushions that uniquely conform to the user's body each time the user sits on the cushion.

Many existing seat cushions use foams and gels to provide comfortable supporting surfaces for the user. One problem with large foam cushions is the overall weight of the cushion. Another problem is that the cost of the material used to form the body portion has risen. Cushion manufacturers thus desire a cushion configuration that minimizes the amount of foam used in order to reduce the weight and cost of the cushion. Cushion manufacturers also desire a cushion configuration that is designed to work with gel materials that are injected as a liquid and cure to a solid soft gel. Although numerous designs exist in the art, room remains for improvement in the art.

BRIEF SUMMARY OF THE INVENTION

The invention provides a cushion having connected upper and lower layers wherein the upper layer includes a plurality of gel pockets and the lower layer includes a plurality of air pockets. In one configuration, each layer may include first and second sheets of material. In another configuration, only three sheets of material are used to form the upper and lower layers. Another configuration aligns the pockets of the upper layer with the pockets of the lower layer. The aspects of the different configurations may be used alone or in combination with each other.

The invention provides a method for forming a cushion that includes the steps of joining first and second sheets together to form a gel chamber; joining third and fourth sheets together to form a gas chamber; connecting the gel chamber to the gas chamber; and at least partially filling the gel chamber with a gel material and filling the gas chamber with a gas.

In another configuration, the invention provides a method for forming a cushion that includes the steps of welding first, second, and third sheets together to form at least one gel pocket and at least one gas pocket; and at least partially filling the gel pocket with a gel material and filling the gas pocket with a gas. In another configuration, a plurality of interconnected pockets are formed for the gel and a plurality of interconnected pockets are formed for the gas. The gel is inserted into the plurality of interconnected pockets in a flowable form and then cured so that it does not migrate from pocket to pocket when subjected to pressure.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic perspective view of an exemplary cushion made in accordance with the concepts of the invention.

FIG. 2 is a section view taken along line 2-2 of FIG. 1.

FIG. 3 is a top plan view of an exemplary six-pocket cushion showing the perimeter weld and two intermediate corner welds.

FIG. 4 is a perspective view of a cover for the cushion.

FIG. 5 is a perspective view of an alternate cover for the cushion of the invention.

Similar numbers refer to similar parts throughout the specification.

DETAILED DESCRIPTION OF THE INVENTION

An exemplary cushion made in accordance with the concepts of the present invention is indicated generally by the number 10 in FIG. 1. Cushion 10 includes an upper layer 12 and a lower layer 14 that are connected together to form an integral cushion 10. Optionally, cushion 10 may be combined with a body layer 16 when placed into service. Body layer 16 is particularly useful for wheelchair applications where a saddle-shaped seat is desired.

Upper layer 12 is formed from a pair of opposed sheets of material (first sheet 30 and second sheet 32). Each sheet 30 and 32 is formed from a weldable, air-impermeable, flexible material. In one embodiment, each sheet is 0.3 mm to 0.8 mm in order to provide desired strength and weld properties. In one embodiment, the material is a polyurethane. When joined together, sheets 30 and 32 define a plurality of pockets 18 that are each interconnected with passageways 33 such that a fluid may flow from pocket 18 to pocket 18. In the exemplary embodiment, the pockets are rectangular.

Lower layer 14 also is formed from first 34 and second 36 sheets of material similar to sheets 30 and 32. When joined together, sheets 34 and 36 define a plurality of pockets 22 that are interconnected to one another such that fluid may flow from pocket 22 to pocket 22. Pockets 22 are filled with a gas such as air. A valve 24 is in communication with at least one pocket 22 and allows all pockets 22 to be filled with the gas and also allows the firmness of lower layer 14 to be varied by selectively adding and removing gas from pockets 22. Valve 24 may be welded between the sheets or through a single sheet before the sheets are welded together.

Upper layer 12 is formed by cutting sheets 30 and 32 to size, overlaying the layers, and welding the layers together to form pockets 18. The welding may be by any welding method useful for welding the sheets of material together. The inventors have found that ultrasonic welding methods are useful. The sheets are welded along their perimeters and at the corners of the pockets so that material may flow from pocket to pocket. In another embodiment, sheets 30 and 32 may also be welded along 1/4 to 1/3 of each pocket 18 sidewall to restrict passageways 33. After sheets 30 and 32 are welded, liquid gel is injected into pockets 18 at an appropriate location. The liquid gel is a type that cures to a solid, non-flowable material. The gel may thus include a catalyst that allows it to cure into a soft solid gel. A polyurethane gel has been found to be useful for this application. Polyurethane and silicone gels may also be used. A gel that remains a fluid may also be used. Pockets 18 may be configured to be substantially filled with gel after the gel is cured. In other embodiments, pockets 18 may be sized to hold both air and gel. The inlet for the gel is then sealed by an appropriate method such as spot welding the inlet. The welding may occur after the gel dries.

Upper layer 14 is formed by cutting sheets 34 and 36 to size, overlaying the layers, and welding the layers together to form pockets 22. The welding may be by any welding method useful for welding the sheets of material together. The inventors have found that ultrasonic welding methods are useful. The sheets are welded along their perimeters and at the corners of the pockets so that material may flow from pocket to pocket. In another embodiment, sheets 34 and 36 may also be welded along 1/4 to 1/2 (from each corner as shown in the drawings) of each pocket 22 sidewall to restrict the passageways between the pockets. For example, each passageway between the pockets may be about 3/8 inch wide on a pocket sidewall of about an inch long. Valve 24 is welded in place and is then used to fill pockets 22 with air. Pockets 22 are arranged to align with pockets 18 when the layers over joined together such that one gel pocket sits immediately above an air pocket.

Layers 12 and 14 are connected together by any of a variety of connection methods that securely connect the layers for use over a long period of time. One method is to weld the layers together at their perimeter edges and/or at the corners of the pockets. Another method is to use an adhesive (such as a urethane adhesive). A further method is to use mechanical connectors that hold the layers together. When welding is used to hold the layers together, the welding may be performed before the layers are filled with the gel and air.

Body layer 16 is a dense foam material such as a polyurethane foam. Body layer 16 may be connected to lower layer 14 with an adhesive such as a urethane glue. The foam material may be a visco-elastic foam material, a high density foam (such as a high density polyurethane foam), and other foams known in the cushion art.

FIG. 4 shows an exemplary cover into which cushion 10 may be placed when in use. Cushion 10 may be fabricated from a breathable waterproof material (i.e.: Tyvek®). Although a flap is shown in the drawing, a zipper may be used to close the cover.

FIG. 5 shows an alternative cover having separated chambers. In this embodiment, upper 12 and lower 14 layers are separated from body layer 16 and placed in the individual chambers when cushion 10 is in use.

In an alternative embodiment of the invention, upper layer 12 is formed without pockets and the gel is placed into a single large pocket that is defined by the entire surface area of upper layer 12. In this alternative embodiment, the upper layer is formed by welding a single sheet of material to the lower layer such that only three sheets are used to form cushion 10. The upper sheet used to form the gel chamber may be welded after the air pockets are welded or simultaneously with the two sheets that are used to form the air pockets.

In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described. 

1. A seating cushion comprising: an upper layer and a lower layer; the upper layer being adapted to be disposed physically above the lower layer when the seating cushion is in use; the upper layer being securely connected to the lower layer; the upper layer including first and second sheets of material; the first and second sheets of material of the upper layer being connected together at selected locations to form a plurality of interconnected pockets; a majority of the interconnected pockets of the upper layer being at least partially filled with a gel; the lower layer including first and second sheets of material; the first and second sheets of material of the lower layer being connected together at selected locations to form a plurality of interconnected pockets; and a majority of the interconnected pockets of the lower layer being at least partially filled with a gas.
 2. The cushion of claim 1, wherein the upper layer is welded to the lower layer with a plurality of welds that also at least partially define the pockets of the upper and lower layers.
 3. The cushion of claim 1, further comprising a resilient foam body layer disposed below the lower layer such that the lower layer is disposed between the upper layer and the resilient foam body layer.
 4. The cushion of claim 3, wherein the lower layer is connected to the body layer with an adhesive.
 5. The cushion of claim 3, wherein the body layer is saddle-shaped.
 6. The cushion of claim 1, wherein a plurality of the sheets are formed from a weldable, air-impermeable, flexible material.
 7. The cushion of claim 6, wherein a plurality of the sheets are polyurethane sheets having a thickness in the range of 0.3 mm to 0.8 mm.
 8. The cushion of claim 1, wherein the pockets of the upper layer are aligned with and disposed over the pockets of the lower layer.
 9. The cushion of claim 1, further comprising a valve carried by the lower layer that allows gas to be selectively added and removed from the plurality of interconnected pockets.
 10. The cushion of claim 1, wherein the gel is a cured solid gel that does not migrate between pockets after being cured.
 11. The cushion of claim 10, wherein the gel includes one of a polyurethane, a silicone, and a mixture including polyurethane and silicone.
 12. A seating cushion comprising: an upper layer of interconnected gel pockets and a lower layer of interconnected gas pockets; the upper layer being adapted to be disposed physically above the lower layer when the seating cushion is in use; a majority of the gel pockets being at least partially filled with a gel; a majority of the gas pockets being at least partially filled with a gas; each layer defining a plurality of sidewalls; each pocket being bounded by at least one sidewall; a plurality of the sidewalls being disposed between adjacent pockets; each sidewall disposed between adjacent pockets defining a passageway that fluidly connects the adjacent pockets; and the upper layer being securely connected to the lower layer.
 13. The cushion of claim 12, wherein the upper layer includes first and second sheets of material; the first and second sheets of material of the upper layer being connected together at selected locations to form the plurality of interconnected pockets; the lower layer including first and second sheets of material; and the first and second sheets of material of the lower layer being connected together at selected locations to form a plurality of interconnected pockets.
 14. The cushion of claim 13, wherein the pockets of the upper layer are aligned with and disposed above the pockets of the lower layer.
 15. The cushion of claim 14, further comprising a valve carried by the lower layer that allows gas to be selectively added and removed from the plurality of interconnected pockets.
 16. The cushion of claim 12, wherein a majority of the pockets are rectangular and bounded by four sidewalls; each of the sidewalls having a length; the passageway having a width; the width of passageway being less than the length of the sidewall the defines the passageway.
 17. A seating cushion comprising: an upper layer of gel pockets and a lower layer of gas pockets; the upper layer being adapted to be disposed physically above the lower layer when the seating cushion is in use; a majority of the gel pockets being at least partially filled with a gel; a majority of the gas pockets being at least partially filled with a gas; and the upper layer being securely connected to the lower layer.
 18. The cushion of claim 17, wherein each layer defines a plurality of corners that define the boundaries of each pocket; each pocket being bounded by at least three corners; and the upper and lower layers being secured together at the corners of the pockets.
 19. The cushion of claim 17, wherein the pockets of the upper layer are aligned with and disposed above the pockets of the lower layer.
 20. The cushion of claim 17, further comprising a cover and a resilient foam body; the cover having an upper chamber and a lower chamber; the upper and lower layers being disposed in the upper chamber of the cover; and the resilient foam body being disposed in the lower chamber of the cover. 